Investment In Unconsolidated Ventures - Summarized Income Statement Information (Detail) - USD ($) $ in Thousands		3 Months Ended								12 Months Ended
		Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Schedule of Equity Method Investments [Line Items]
Revenues										$ 65,748	$ 46,130	$ 125,729
Earnings (Loss)										39,150	9,119	59,320
Our share of earnings (loss)		$ 7,026	$ 1,764	$ 2,747	$ 6,362	$ 2,251	$ 3,637	$ 188	$ 47	17,899	6,123	16,008
242, LLC
Schedule of Equity Method Investments [Line Items]
Revenues	[1],[2]									13,073	5,835	20,995
Earnings (Loss)	[1],[2]									8,021	1,259	9,588
Our share of earnings (loss)	[1],[2]									4,096	668	4,919
CL Ashton Woods
Schedule of Equity Method Investments [Line Items]
Revenues	[2]									3,179	2,870	9,820
Earnings (Loss)	[2]									1,456	914	3,881
Our share of earnings (loss)	[2]									1,816	1,332	5,000
CL Realty
Schedule of Equity Method Investments [Line Items]
Revenues										499	567	856
Earnings (Loss)										(1,155)	237	424
Our share of earnings (loss)										(578)	119	212
CREA FMF
Schedule of Equity Method Investments [Line Items]
Revenues	[1],[2]									5,440	4,955	1,227
Earnings (Loss)	[1],[2]									17,267	(1,420)	(1,696)
Our share of earnings (loss)	[1],[2]									7,563	1,103	(1,696)
Elan 99 LLC
Schedule of Equity Method Investments [Line Items]
Revenues										4,596	1,392	0
Earnings (Loss)										(1,896)	(2,739)	(49)
Our share of earnings (loss)										(1,712)	(2,465)	(44)
FMF Littleton
Schedule of Equity Method Investments [Line Items]
Revenues										6,366	3,116	120
Earnings (Loss)										192	(571)	(367)
Our share of earnings (loss)										48	(143)	(92)
FMF Peakview
Schedule of Equity Method Investments [Line Items]
Revenues										0	939	2,057
Earnings (Loss)										0	(248)	(1,116)
Our share of earnings (loss)										0	(50)	(223)
FOR/SR Forsyth LLC
Schedule of Equity Method Investments [Line Items]
Revenues										0	0	0
Earnings (Loss)										(148)	(65)	0
Our share of earnings (loss)										(134)	(58)	0
HM Stonewall Estates
Schedule of Equity Method Investments [Line Items]
Revenues	[3]									496	2,112	3,990
Earnings (Loss)	[3]									243	832	1,881
Our share of earnings (loss)	[3]									103	361	952
LM Land Holdings
Schedule of Equity Method Investments [Line Items]
Revenues	[3]									22,127	10,001	10,956
Earnings (Loss)	[3]									10,629	7,288	8,251
Our share of earnings (loss)	[3]									3,563	2,458	3,342
MRECV DT Holdings LLC
Schedule of Equity Method Investments [Line Items]
Revenues	[4]									1,196	495	0
Earnings (Loss)	[4]									1,173	477	167
Our share of earnings (loss)	[4]									911	429	0
MRECV Edelweiss LLC/MRECV Lender VIII LLC
Schedule of Equity Method Investments [Line Items]
Revenues										1,018	416	0
Earnings (Loss)										1,016	409	151
Our share of earnings (loss)										789	368	137
MRECV Juniper Ridge LLC
Schedule of Equity Method Investments [Line Items]
Revenues	[4]									1,445	379	0
Earnings (Loss)	[4]									1,445	380	106
Our share of earnings (loss)	[4]									1,089	342	0
MRECV Meadow Crossing II LLC
Schedule of Equity Method Investments [Line Items]
Revenues										638	267	0
Earnings (Loss)										638	220	0
Our share of earnings (loss)										496	198	0
Miramonte Boulder Pass, LLC
Schedule of Equity Method Investments [Line Items]
Revenues	[4]									5,483	4,923	0
Earnings (Loss)	[4]									177	(399)	(250)
Our share of earnings (loss)	[4]									(197)	(200)	(125)
PSW Communities
Schedule of Equity Method Investments [Line Items]
Revenues										0	0	29,986
Earnings (Loss)										0	0	2,688
Our share of earnings (loss)										0	0	1,169
Temco
Schedule of Equity Method Investments [Line Items]
Revenues										192	1,344	9,485
Earnings (Loss)										92	440	2,358
Our share of earnings (loss)										46	220	1,179
Other Ventures
Schedule of Equity Method Investments [Line Items]
Revenues										0	6,519	36,237
Earnings (Loss)										0	2,105	33,303
Our share of earnings (loss)										$ 0	$ 1,441	$ 1,278

[1] Includes unamortized deferred gains on real estate contributed by us to ventures. We recognize deferred gains as income as real estate is sold to third parties. Deferred gains of $548,000 are reflected as a reduction to our investment in unconsolidated ventures at year-end 2017.

[2] Our share of venture earnings in 2016 includes reallocation of prior year cumulative losses incurred by the venture as a result of equity contribution by the venture partner in 2016

[3] Includes unrecognized basis difference of $448,000 which is reflected as an increase of our investment in unconsolidated ventures at year-end 2017. This difference will be amortized as expense over the life of the investment and included in our share of earnings (loss) from the respective venture.

[4] Please read Note 22 - Subsequent Event for additional information regarding this transaction.